Web Server Renders User HTML Leading to XSS
February 6, 2024
Our fifth vulnerability was a Cross-Site Scripting (XSS) vulnerability discovered in the web server component. Whenever users submit an artifact, they can also report samples, such as images, that are displayed under the debug samples tab. When submitting an image, a user can provide a URL rather than uploading an image. However, if the URL has the extension .html, the web server retrieves the HTML page, which is assumed to contain trusted data. The HTML is passed to the bypassSecurityTrustResourceUrl function, marking it as safe and rendering the code on the page, resulting in arbitrary JavaScript running in any user’s browser when they view the samples tab.
Related SAI Security Advisory
November 26, 2025
Allowlist Bypass in Run Terminal Tool Allows Arbitrary Code Execution During Autorun Mode
When in autorun mode with the secure ‘Follow Allowlist’ setting, Cursor checks commands sent to run in the terminal by the agent to see if a command has been specifically allowed. The function that checks the command has a bypass to its logic, allowing an attacker to craft a command that will execute non-whitelisted commands.
October 17, 2025
Data Exfiltration from Tool-Assisted Setup
Windsurf’s automated tools can execute instructions contained within project files without asking for user permission. This means an attacker can hide instructions within a project file to read and extract sensitive data from project files (such as a .env file) and insert it into web requests for the purposes of exfiltration.